Split using plane size?

I am trying to make a script that creates mitred corners. I thought of creating a plane and then calling opSplit. But then I realised that the plane is infinite and will not just split the desired corner, but the whole part. Is there a way of setting an "effect radius"? Such that it will only split a part in a certain radius.If not, what will be the best way of making mitred corners using featurescript?

There are 10 types of people in the world. Those who know binary, those who don't and those who didn't expect base 3!

Comments

A chamfer won't work in this scenario. I am creating a rectangle and then a smaller rectangle inside it then extruding the profile, so the result is a hollow box. Then I want to create the mitred corners but this is my resultSo you can see it has split the corner, but it has extended past and split the back face. I would like to prevent this. I know that this is because the plane is infinite, but it would be nice if the split stopped at the boundary of the plane object.

There are 10 types of people in the world. Those who know binary, those who don't and those who didn't expect base 3!